The resistance of the filament of a lamp increases with the increase in temperature. A lamp rated ${\rm{100 W}}$ and ${\rm{200 V}}$ is connected across ${\rm{200 V}}$ power supply. If the voltage drops by ${\rm{10}}\,\,{\rm{\% }}$, then the power of the lamp will be

Between ${\rm{81}}\,\,{\rm{and}}\,\,{\rm{90}}\,\,{\rm{W}}$

Between ${\rm{90}}\,\,{\rm{and}}\,\,{\rm{100}}\,\,{\rm{W}}$

JEE PHYSICS MCQ: CURRENT ELECTRICITY

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The resistance of the filament of a lamp increases with the increase in temperature. A lamp rated

\mathrm{100 W}

and

\mathrm{200 V}

is connected across

\mathrm{200 V}

power supply. If the voltage drops by

\mathrm{10}\,\,\mathrm{\% }

, then the power of the lamp will be

View answer and explanation

Correct option: D

Between

\mathrm{81}\,\,\mathrm{and}\,\,\mathrm{90}\,\,\mathrm{W}

Option D (Between

\mathrm{81}\,\,\mathrm{and}\,\,\mathrm{90}\,\,\mathrm{W}

) is correct because the resistance decreases with lower temperature, leading to a power output greater than 81W but less than 90W.